Sheoldred and Wizard Class trigger for each card drawn.
Resolve all Sheoldred triggers, causing you to gain 2 life for each trigger.
Resolve the first Wizard Class trigger, putting a +1/+1 counter on Fetid Gargantua.
Fetid Gargantua triggers, causing you to draw two cards and lose 2 life.
Repeat from step 2.
This loop turns a single drawn card into an explosive, self-sustaining chain reaction by exploiting the brilliant synergy between Wizard Class and Sheoldred, the Apocalypse. Once Wizard Class reaches level 3, every card drawn places a +1/+1 counter on Fetid Gargantua, which in turn triggers its ability to draw two more cards and lose 2 life. To keep you from bleeding out, Sheoldred, the Apocalypse steps in to completely neutralize that life loss by granting you 2 life for every single card drawn.